1. Field of the Invention
The present invention relates to a short circuit detecting method for detecting a short circuit condition of wirings or the like on a semiconductor substrate and a semiconductor device used for short circuit detection.
2. Description of the Related Art
In a semiconductor device, an electrical short circuit in a wiring or a conductor becomes a fatal. defect and reduces the yield of the semiconductor device. For example, a short circuit defect is caused because a conductive foreign object adheres onto a wiring and extends to a wiring adjacent thereto. In detecting such a short circuit defect, inspection is performed using a defect inspector, and then confirmation is made by review with a review system, for example, including an SEM. Similarly, a short circuit caused by a pattern failure between wirings is also confirmed by inspection and review. The presence or absence of these defects can be easily judged by observation from above with the SEM at the time of the review.
(Patent Document 1)
Japanese Patent Application Laid-open No. 2001-305194
(Patent Document 2)
Japanese Patent Application Laid-open No. 2002-203882
However, with the scale down and high-density integration of semiconductor elements in recent times, a so-called coating-type low dielectric constant interlayer insulating film comes to be used as a material for an insulating film between wirings. In the case of the coating-type one, unlike an interlayer insulating film formed by a CVD method or the like, a conductive foreign object is sometimes mixed into the interlayer insulating film when the interlayer insulating film is applied, and this foreign object causes a short circuit defect between the wirings. In this case, since the foreign object exists in the film, defect coordinates cannot be detected by ordinary defect inspection, or even if the defect coordinates are detected by allowing a detection beam of the defect inspection to pass through the film, a distinct image of the foreign object cannot be confirmed by the observation with the SEM at the time of review, whereby it is difficult to detect the short circuit in the film as a short circuit defect. Also in product defect inspection performed in a factory process, such a short circuit defect in the interlayer insulating film cannot be detected.
For example, as a detecting method of a short circuit defect position in the interlayer insulating film, a technique in Patent Document 1 is cited. As in Patent Document 1, there is disclosed a semiconductor device for inspection in which pairs of rectangular conductor traces are arranged in a staggered format, one of each pair being electrically connected to a semiconductor substrate and the other being electrically insulated therefrom. However, in this case, the number of connecting portions between one conductor trace and the semiconductor substrate is small (one in the example shown), whereby when a connection failure occurs between the one conductor trace and the semiconductor substrate, there is a problem that this connection failure is detected as an electric defect and becomes noise in short circuit detection, which significantly reduces the accuracy of the short circuit defect detection.